High Magnification Compact Zoom Lens

ABSTRACT

The present invention is directed to high magnification compact zoom lenses that are reduced in diameter of groups of lens pieces closer to the imaging plane to provide downsized lightweight zoom lenses of magnification as high as 20 diameters, with an image stabilizer or vibration compensating mechanism being also reduced in dimensions. An exemplary improved high magnification zoom lens has four groups of lens pieces, namely, the first or leading lens group G 1  of positive refractivity in the foremost position closer to the subject, the second lens group G 2  of negative refractivity, the third lens group G 3  of positive refractivity, and the fourth lens group G 4  of positive refractivity in the rearmost position closer to the imaging plane, all arranged in this order. In displacing the entire lens optics of the zoom lens from the wide-angle end to the telephoto end, the second lens group G 2  are moved toward the imaging plane and the fourth lens group G 4  are moved to compensate for a varied position of the resultant image while the first and third lens groups, G 1  and G 3 , have their respective positions fixed along the optical axis. The zoom lens satisfies the requirements as defined in the following formulae: f 3 /f 4 &gt;2.0 and v 4 &gt;65 where f 3  is a focal length of the third lens group G 3 , f 4  is the focal length of the fourth lens group, v 4  is an average of Abbe contrasts of all the convex lens pieces in the fourth lens group G 4.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. application Ser. No.12/457,141, filed Jun. 2, 2009, which claims priority to JapaneseApplication No. 2008-147126, filed Jun. 4, 2008, Japanese ApplicationNo. 2008-147127, filed Jun. 4, 2008, and Japanese Application No.2008-147128, filed Jun. 4, 2008, and which are hereby incorporated byreference in their entireties.

FIELD OF THE INVENTION

The present invention relates to compact zoom lenses of magnification ashigh as 20 diameters that are suitable for optical apparatuses, such asvideo cameras, digital still cameras, and the like, having a pluralityof imaging devices integrated therein.

In general, cameras having an increased number of integrated imaging arerequired to correspondingly have a longer back focus, namely, a longerdistance from the rearmost surface of the lens to the imaging plane. Inone well known example of wide-view zoom lenses suitable for videocameras, digital still cameras, and the like that use an opto-electricalconverter to opto-electrically convert rays reflected from the subjectinto signals, there are four groups of lens pieces arranged to exerttheir respective optical attributes of refractive power likepositive-negative-positive-positive in this order.

Typically, with lens optics of high zoom ratio, an image obtained at thetelephoto end is reduced in angle of field and increased inmagnification, which results in minute tremors of the hand(s) causingthe image to blur. One typical solution to such a blur of the image isan image stabilizer or an optical vibration compensation mechanism that,for the purpose of correcting blur, allows part of the lens optics to beshifted in directions perpendicular to the optical axis to guideincident beams so that they can be imaged in shifted area perpendicularto the optical axis within the imaging plane.

In order to compensate for varied imaging positions due to tremors ofthe hand(s), part of the third group of lens pieces, for instance, threeof the lens pieces may be moved in directions orthogonal to the opticalaxis (see Patent Document 1 listed below).

In another prior art embodiment where the improved anti-vibrating groupof lens pieces is successfully downsized, part of the third group oflens pieces, namely, only two of the lens pieces are to be moved indirections orthogonal to the optical axis.

Patent Document 1

-   Japanese Patent Preliminary Publication of Unexamined Application    No. 2007-3776

Patent Document 2

-   Japanese Patent Preliminary Publication of Unexamined Application    No. 2007-127694

Patent Document 3

-   Japanese Patent Preliminary Publication of Unexamined Application    No. 2007-212847

In the zoom lens disclosed in Patent Document 1, as it is displaced fromthe wide-angle end to the telephoto end, four of the lens groups maketheir respective separate motions; i.e., the second group of lens piecesare moved toward the imaging plane, the fourth group of lens pieces areshifted to compensate for a variation in the imaging plane, and thefirst and third groups of lens pieces are fixed in positions along theoptical axis where these four lens groups are arranged so as to exerttheir respective optical attributes of refractive power as positive,negative, positive, and positive in order on the closest to the subjectfirst basis. The third lens group includes the leading subset of lenspieces of negative refractivity followed by the trailing subset of lenspieces of positive refractivity closer to the imaging plane, andshifting the positive subset of lens pieces in directions orthogonal tothe optical axis permits the incident beams to be guided and imaged inshifted area orthogonal to the optical axis where the optics of the zoomlens satisfies requirements defined in numerical relations.

The numerical relations can be expressed in the formulae as follows:

1.4<|f3n|/f3<3  (1)

−0.3<(Rn+Rp)/(Rn−Rp)<0.3  (2)

0<(Rp1+Rp2)/(Rp1−Rp2)<2  (3)

0.42<|f2|/(fw·ft)^(1/2)<0.5  (4)

0.8<Dt/Z2<1.2  (5)

where f3 n is a focal length of the negative subset of lens pieces inthe third lens group, f2 is the focal length of the second lens group,f3 is the focal length of the third lens group, fw is the focal lengthof the zoom lens at the wide-angle end, ft is the focal length of thezoom lens at the telephoto end, Rp1 is a radius of curvature of thefront surface of the rearmost positive lens piece in the positive subsetof lens pieces of the third lens group, Rp2 is the radius of curvatureof the opposite or rear surface of the rearmost positive lens piece inthe positive subset of lens pieces of the third lens group, Dt is adistance along the optical axis from an aperture stop to the rearsurface of the rearmost lens piece in the fourth lens group at thetelephoto end, and Z2 is a displacement of the second group of lenspieces when the zoom lens is displaced from the wide-angle end to thetelephoto end.

A zooming feature of the zoom lens disclosed in the cited PatentDocument 1 has negative and positive subsets of lens pieces disposed inthe third lens group, with three of component lens pieces in total inthe positive subset. These three lens pieces, which are greater ineffective diameter than those in the negative subset, are accordinglygreater in weight, and therefore, an image stabilizer or vibrationcompensation mechanism should resultantly be increased in dimensions. Anadditional problem is that, in order to shorten the focusing distance orthe minimum working distance from the subject to the zoom lens at itstelephoto end, the fourth lens group should accordingly have the greatereffective diameter, resulting in increased power consumption required tomove the fourth lens group for the focusing.

In the zoom lens disclosed in Patent Document 2, as it is displaced fromthe wide-angle end to the telephoto end, four of the lens groups maketheir respective separate motions; i.e., the second group of lens piecesare moved toward the imaging plane, the fourth group of lens pieces areshifted to compensate for a variation in the imaging plane, and thefirst and third groups of lens pieces are fixed in positions along theoptical axis where these four lens groups are arranged so as to exerttheir respective optical attributes of refractive power as positive,negative, positive, and positive in this order. The third lens groupincludes the leading subset of lens pieces of negative refractivityfollowed by the trailing subset of lens pieces of positive refractivitycloser to the imaging plane, and shifting the positive subset of lenspieces in directions orthogonal to the optical axis permits the incidentbeams to be guided and imaged in shifted area orthogonal to the opticalaxis where the optics satisfies requirements defined in numericalrelations.

The numerical relations featured by the zoom lens with the quartet-lensoptics can be expressed in the formulae as follows:

1.2<|f3n|/f4  (6)

0.9<f3p/f4  (7)

0.2<|1/Ra+1/Rb|·fw<0.4  (8)

where f3 n is a focal length of the negative subset of lens pieces inthe third lens group, f3 p is the focal length of the positive subset oflens pieces in the third lens group, f4 is the focal length of thefourth lens group, fw is the focal length of the entire optics of thezoom lens at the wide-angle end, Ra is a radius of curvature of thefront surface of a negative lens piece in the negative subset of thethird lens group, and Rb is the radius of curvature of the front surfaceof a positive lens piece in the negative subset of the third lens group.

A zooming feature of the zoom lens disclosed in the cited PatentDocument 2 has negative and positive subsets of lens pieces disposed inthe third lens group, with two of cemented doublets disposed in thepositive subset. These two lens pieces in the positive subset, which aregreater in effective diameter than those in the negative subset, areaccordingly greater in weight, and therefore, an image stabilizer or avibration compensating mechanism should resultantly be increased indimensions. An additional problem is that, in order to shorten thefocusing distance of the zoom lens at its telephoto end, the fourth lensgroup should have a greater effective diameter, resulting in increasedpower consumption required to move the fourth lens group for thefocusing.

In the zoom lens disclosed in Patent Document 3, the four lens groupsare arranged so as to exert their respective optical attributes ofrefractive power as positive, negative, positive, and positive in orderon the closest to the subject first basis, where the third lens groupincludes a fixed subset of lens pieces of negative refractivity and amovable subset of lens pieces of positive refractivity that can beshifted in directions orthogonal to the optical axis so as to compensatefor varied imaging positions resulted from the optical axis perturbed.The optics of the zoom lens satisfies requirements defined in numericalrelations.

The numerical relations featured by the zoom lens with the quartet-lensoptics can be expressed in the formulae as follows:

−2<SAB·FN ² ·fw/f32<−0.1  (9)

−0.9<SAA/SAB<−0.003  (10)

|S2/f31|≦0.15  (11)

S2/f32≦0.2  (12)

where fw is a focal length of the entire optics of the zoom lens at thewide-angle end, FN is a maximized F number of the zoom lens at thewide-angle end, SAA is a numerical representation of sphericalaberration caused in the zoom lens at the wide-angle end with themaximized F number under the condition of full aperture as a result ofreplacing an aspherical surface of the lens piece(s) in the negativesubset of the third lens group with its paraxial spherical surface, SABis the numerical representation of the spherical aberration caused inthe lens optics at the wide-angle end with the maximized F numberresulted from replacing the aspherical surface of the lens piece(s) inthe positive subset of the third lens group with its paraxial sphericalsurface, f31 is the focal length of the negative subset of the thirdlens group, f32 is the focal length of the positive subset of third lensgroup, and S2 is an interval of the air gap between the second and thirdlens groups of the zoom lens at the telephoto end.

In the zoom lens as disclosed in the cited Patent Document 3, theaperture stop is disposed in the third group of lens pieces,specifically, it is between the negative subset of lens pieces closer tothe subject and the positive subset of lens pieces closer to the imagingplane. The positive subset include two of the component lens pieces,which are greater in effective diameter than those in the negativesubset and accordingly greater in weight, and therefore, an imagestabilizer or a vibration compensating mechanism should resultantly beincreased in dimensions. An additional problem is that, in order toshorten the closest focusing distance from the subject to the zoom lensat its telephoto end, the fourth lens group should accordingly have thegreater effective diameter, resulting in increased power consumptionrequired to move the fourth lens group for the focusing.

The present invention is made to overcome the aforementioned problems inthe prior art high magnification compact zoom lenses, and accordingly,it is an object of the present invention to provide the improved compactzoom lens of magnification as high as 20 diameters that is reduced inboth dimensions and weight by providing component lens groups ofdecreased diameter in positions closer to the imaging plane and that hasits image stabilizer or vibration compensating mechanism reduced indimensions as well.

It is another object of the present invention to provide the improvedhigh magnification compact zoom lens that has the reduced focusingdistance at the telephoto end down to ten times as long as or rathershorter than the focal length at the telephoto end.

It is still another object of the present invention to provide theimproved high magnification compact zoom lens that has one or more ofthe component lens pieces formed with an aspherical surface on at leastone of the opposite sides thereof in the lens group(s) closer to theimaging plane, so as to satisfactorily compensate for chromaticaberration and spherical aberration.

It is further another object of the present invention to provide theimproved high magnification wide-view zoom lens that is capable ofsatisfactorily compensating for various types of aberration and thatattains an enhanced zooming ratio as high as 20 diameters and a greaterangle of view of 75 degrees or even wider at the wide-angle end.

It is yet another object of the present invention to provide theimproved zoom lens that has downsized anti-vibration lens group drivenwith the reduced power and that can achieve a well-balanced compensationfor various types of aberration throughout the full zoom range.

SUMMARY OF THE INVENTION

In a first aspect of the present invention, a high magnification compactzoom lens has four groups of lens pieces, namely, the first or leadinglens group G1 of positive refractivity in the foremost position closerto the subject, the second lens group G2 of negative refractivity, thethird lens group G3 of positive refractivity, and the fourth lens groupG4 of positive refractivity in the rearmost position closer to theimaging plane, all arranged in this order. In displacing the entire lensoptics of the zoom lens from the wide-angle end to the telephoto end,the second lens group G2 are moved toward the imaging plane and thefourth lens group G4 are moved to compensate for a varied position ofthe resultant image while the first and third lens groups, G1 and G3,have their respective positions fixed along the optical axis. The zoomlens is characterized in that it satisfies the requirements as definedin the following formulae:

f3/f>2.0  (13)

v4>65  (14)

where f3 is a focal length of the third lens group G3, f4 is the focallength of the fourth lens group G4, and v4 is an average of Abbeconstants of all the convex lens pieces in the fourth lens group G4.

In this aspect of the present invention, the fourth lens group G4 hasone or more of the lens pieces provided with an aspherical surface on atleast one of the opposite sides thereof.

In a second aspect of the present invention, a high magnificationcompact zoom lens has four groups of lens pieces, namely, the first orleading lens group G1 of positive refractivity in the foremost positioncloser to the subject, the second lens group G2 of negativerefractivity, the third lens group G3 of positive refractivity, and thefourth lens group G4 of positive refractivity in the rearmost positioncloser to the imaging plane, all arranged in this order. In displacingthe entire lens optics of the zoom lens from the wide-angle end to thetelephoto end, the second lens group G2 are moved toward the imagingplane and the fourth lens group G4 are moved to compensate for a variedposition of the resultant image while the first and third lens groups,G1 and G3, have their respective positions fixed along the optical axis.The zoom lens is characterized in that it satisfies the requirements asdefined in the following formulae:

f3/f4>2.0  (13)

6.0<BFw/Y<8.0  (15)

where f3 is a focal length of the third lens group G3, f4 is the focallength of the fourth lens group G4, BFw is a distance between a rearmostsurface of the fourth lens group G4 (that is, the rearmost surface ofthe trailing lens piece of the fourth lens group G4) and the imagingplane at the wide-angle end, and Y is a height of the greatest imagecreated in the imaging plane.

In a third aspect of the present invention, a high magnificationwide-view zoom lens has four groups of lens pieces, namely, the first orleading lens group G1 of positive refractivity in the foremost positioncloser to the subject, the second lens group G2 of negativerefractivity, the third lens group G3 of positive refractivity, and thefourth lens group G4 of positive refractivity in the rearmost positioncloser to the imaging plane, all arranged in this order. In displacingthe entire lens optics of the zoom lens from the wide-angle end to thetelephoto end, the second lens group G2 are moved toward the imagingplane and the fourth lens group G4 are moved to compensate for a variedposition of the resultant image while the first and third lens groups,G1 and G3, have their respective positions fixed along the optical axis.The zoom lens is characterized in that it satisfies the requirements asdefined in the following formula:

|f1/f2|>6.5  (16)

where f1 is focal length of the first lens group G1, and f2 is the focallength of the second lens group G2.

In the third aspect of the invention, the high magnification wide-viewzoom lens satisfies the requirements as defined in the followingformula:

0.4<|f1₁/(v1×fw)|<0.6  (17)

where f1 ₁ is the focal length of the foremost or leading lens piece ofthe first lens group G1, v1 is an Abbe constant of the foremost orleading lens piece of the first lens group G1, and fw is the focallength of the zoom lens at the wide-angle end.

In a fourth aspect of the present invention, a high magnificationwide-view zoom lens has four groups of lens pieces, namely, the first orleading lens group G1 of positive refractivity in the foremost positioncloser to the subject, the second lens group G2 of negativerefractivity, the third lens group G3 of positive refractivity, and thefourth lens group G4 of positive refractivity in the rearmost positioncloser to the imaging plane, all arranged in this order. In displacingthe entire lens optics of the zoom lens from the wide-angle end to thetelephoto end, the second lens group G2 are moved toward the imagingplane and the fourth lens group G4 are moved to compensate for a variedposition of the resultant image while the first and third lens groups,G1 and G3, have their respective positions fixed along the optical axis.The zoom lens is characterized in that it satisfies the requirements asdefined in the following formulae:

|f1/f2|>6.59  (16)

0.4<|f1₁/(v1×fw)|<0.6  (17)

where f1 is a focal length of the first lens group G1, f2 is the focallength of the second lens group G2, f1 ₁ is the focal length of theforemost or leading lens piece of the first lens group G1, v1 is an Abbeconstant of the foremost lens piece of the first lens group G1, and fwis the focal length of the zoom lens at the wide-angle end. The zoomlens is also characterized in that second lens group G2 has one or moreof the lens pieces provided with an aspherical surface on at least oneof the opposite sides thereof.

In a fifth aspect of the invention, a wide-view anti-vibration zoom lenshas four groups of lens pieces, namely, the first or leading lens groupG1 of positive refractivity in the foremost position closer to thesubject, the second lens group G2 of negative refractivity, the thirdlens group G3 of positive refractivity, and the fourth lens group G4 ofpositive refractivity in the rearmost position closer to the imagingplane, all arranged in this order. In displacing the entire lens opticsof the zoom lens from the wide-angle end to the telephoto end, thesecond lens group G2 are moved toward the imaging plane and the fourthlens group G4 are moved to compensate for a varied position of theresultant image while the first and third lens groups, G1 and G3, havetheir respective positions fixed along the optical axis.

The zoom lens being characterized in that the third lens group G3 has afixed lens subset L31 of a convexo-concave cemented lens followed by amovable lens subset L32 of a concavo-convex cemented lens, the movablelens subset L32 being shifted in directions orthogonal to the opticalaxis so as to cause incident beams to be imaged in shifted position, andthe fixed lens subset L31 has its convex surface of the greatercurvature faced closest to the subject and its concave surface of thegreater curvature faced closest to the imaging plane, and that the zoomlens satisfies the requirements as defined in the following formulae:

H31>H32  (18)

where H31 is a height of part of incident beams on the foremost surfaceof the leading lens piece in the fixed lens subset L31 of the third lensgroup G3 on or above the optical axis at the wide-angle end, and H32 isthe height of part of the incident beams on the foremost surface of theleading lens piece in the movable or image-stabilizing lens subset L32of the third lens group G3 on or above the optical axis at thewide-angle end, and

−0.12<(R31−R32)/(R31+R32)<0.12  (19)

where R31 is a radius of curvature of the convex surface of the leadinglens piece closest to the subject in the fixed lens subset L31 of thethird lens group G3, and R32 is the radius of curvature of the concavesurface of the trailing lens piece closest to the imaging plane in thefixed lens subset L31 of the third lens group G3.

In this aspect of the present invention, the fixed lens subset L31 inthe third lens group has one or more of the lens pieces provided with anaspherical surface on at least one of the opposite sides thereof so asto compensate for comatic aberration and spherical aberration.

<Requirements of the Invention>

Assuming that f3 is the focal length of the third lens group G3, and f4is the focal length of the fourth lens group G4, the requirement asdefined in the formula (13) f3/f4>2.0 represents a condition in whichthe third and fourth lens groups can be downsized and reduced in weight,and simultaneously, the closest focusing distance from the subject tothe leading end of the zoom lens can be ten times as long as or evenshorter than the focal length of the zoom lens at the telephoto end.Thus, if the quotient of the focal length of the third lens group G3divided by that of the fourth lens group G4 is equal to or smaller thanthe lower limit as given in the formula (13), both of the improvedfeatures of the invention are unattainable, that is, the third andfourth lens groups cannot be downsized and reduced in weight, and thefocusing distance cannot be ten times as long as or even shorter thanthe focal length of the zoom lens at the telephoto end.

Assuming now that v4 is the average of Abbe constants of all the convexlens pieces in the fourth lens group G4, the requirement as defined inthe formula (14) v4>65 expresses a condition in which chromaticaberration and spherical aberration are well compensated when the zoomlens at the telephoto end has the focus set either at the infinitivedistance or at the closest focusing distance. Thus, the value of v4 isequal to or smaller than the lower limit as given in the formula (14),the zoom lens at the telephoto end, which is in focus either at theinfinity point or the closest focusing distance, cannot compensate forthe chromatic aberration and the spherical aberration.

The requirement as defined in the formula (15) 6.0<BFw/Y<8.0 expresses acondition in which the zoom lens is permitted to have a long back focusand the fourth lens group reduced in dimensions. If BFw/Y is equal to orsmaller than the lower limit of 6.0, the back focus comes short of theposition of a 3-CCD fixed dichroic prism. In addition, if BFw, which isa distance from the rearmost surface of the trailing lens piece in thefourth lens group G4 to the imaging plane, exceeds the upper limit of8.0 at the wide-angle end, that distance between the imaging plane andthe lens surface closest to the imaging plane is extended at thewide-angle end, and a focusing subset of lens pieces in the fourth lensgroup G4 inevitably has a greater diameter in order to retain theequalized performance in terms of luminous factors such as light loss,which resists the intended effect of downsizing.

Providing one or more of the lens pieces in the fourth lens group G4with an aspherical surface at least one of the opposite sides thereof isthe condition of having the zoom lens effect well-balanced compensationfor the comatic aberration and the spherical aberration.

The formula (16) defined as |f1/f2|>6.5 represents conditions requiredto widen an angle of view and to effectively correct various types ofaberration such as distortion aberration, astigmatism, and the like soas to obtain satisfactory optical performance. If the absolute value off1/f2 is equal to or smaller than the lower limit given in the formula(16), it is difficult to correct the comatic aberration and thedistortion aberration, especially, these of aberration caused in thezoom lens at the wide-angle end.

The formula (17) defined as 0.4<f1 ₁/(v1×fw)|<0.6 expresses conditionsof optimizing the power and Abbe constant of the first lens group G1 andof satisfactorily compensating for chromatic aberration caused in thezoom lens at high magnifications. If the absolute value of f1 ₁/(v1×fw)is equal to or smaller than the lower limit given in the formula (17),it is difficult to correct the chromatic aberration in the longerwavelength range, and if it exceeds the higher limit in the formula(17), it is hard to compensate for the chromatic aberration in theshorter wavelength range, resultantly leading to a difficulty inwidening the angle of view.

Providing one or more of the lens pieces in the second lens group G2with an aspherical surface on at least one of the opposite sides thereofenables to efficiently compensate for the distortion aberration andastigmatism caused in the zoom lens at the wide-angle end.

The formula (18) is for reducing an effective diameter of theanti-vibration lens subset. If it does not meet the requirement definedin the formula (18), the anti-vibration lens subset must have a greaterdiameter, and this causes the resultant wide-view anti-vibration zoomlens to increase in both dimensions and weight and have to have ahigher-powered driving mechanism for such anti-vibration lens subset.

The formula (19) is given for the purpose of attaining theanti-vibration lens subset of reduced effective diameter andsatisfactorily correcting the comatic aberration and the sphericalaberration as well. If the quotient of (R31−R32)/(R31+R32) is equal toor smaller than the lower limit as given in the formula (19), theanti-vibration lens subset, which is reduced in power, has to shift morefor the same effect and be followed by the succeeding lens subsets thatresultantly necessitate to increase in dimensions, which isdisadvantageous in downsizing the zoom lens. If it exceeds the upperlimit given in the formula (19), the anti-vibration lens subset, whichis raised in power, results in likely failing to compensate for thecomatic aberration and the spherical aberration.

EFFECTS OF THE INVENTION

In the high magnification compact zoom lens according to the presentinvention, the groups of lens pieces closer to the imaging plane arereduced in diameter to have the resultant zoom lens downsized andreduced in weight, retaining a magnification as high as 20 diameters,and the integrated image stabilizer or the vibration compensatingmechanism is also reduced in dimensions.

Also in the high magnification compact zoom lens according to thepresent invention, the closest focusing distance at the telephoto end isten times as long as or even smaller than the focal length at thetelephoto end.

Additionally, in the high magnification compact zoom lens according tothe present invention, one or more of the lens pieces in any lens groupcloser to the imaging plane has an aspherical surface on at least one ofthe opposite sides thereof so as to satisfactorily compensate for thechromatic aberration and the aspherical aberration.

In the high magnification wide-view zoom lens according to the presentinvention, various types of aberration are corrected well, and theresultant zoom lens is enhanced in magnification as high as 20 diametersand has a field of view of 75 degrees or even wider at the wide-angleend.

In the wide-view anti-vibration zoom lens according to the presentinvention, magnification ratios can be raised as high as those enabledin cameras that employ imaging devices, and image blur resulted fromtremors of the hand(s) and/or other vibrations can be opticallycorrected. In addition, well-balanced compensation for various types ofaberration can be guaranteed throughout the zoom range, and theanti-vibration lens subset reduced in diameter necessitates a reducedpower to actuate them.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of optics of a first preferred embodiment ofa wide-view anti-vibration zoom lens in accordance with the presentinvention.

FIG. 2 is a graphical view depicting spherical aberration, astigmatism,and distortion aberration caused in the exemplary wide-viewanti-vibration zoom lens at the wide-angle end.

FIG. 3 is a graphical view depicting the spherical aberration,astigmatism, and distortion aberration caused in the exemplary wide-viewanti-vibration zoom lens at the telephoto end.

FIG. 4 is a graphical view depicting comatic aberration caused in theexemplary wide-view anti-vibration zoom lens at the wide-angle end.

FIG. 5 is a graphical view depicting the comatic aberration caused inthe exemplary wide-view anti-vibration zoom lens at the telephoto end.

FIG. 6 is a sectional view showing the optics of a second preferredembodiment of the wide-view anti-vibration zoom lens in accordance withthe present invention.

FIG. 7 is a graphical view depicting spherical aberration, astigmatism,and distortion aberration caused in the exemplary wide-viewanti-vibration zoom lens at the wide-angle end.

FIG. 8 is a graphical view depicting the spherical aberration,astigmatism, and distortion aberration caused in the exemplary wide-viewanti-vibration zoom lens at the telephoto end.

FIG. 9 is a graphical view depicting the comatic aberration caused inthe exemplary wide-view anti-vibration zoom lens at the wide-angle end.

FIG. 10 is a graphical view depicting the comatic aberration caused inthe exemplary wide-view anti-vibration zoom lens at the telephoto end.

FIG. 11 is a sectional view showing the optics of a third preferredembodiment of the wide-view anti-vibration zoom lens in accordance withthe present invention.

FIG. 12 is a graphical view depicting the spherical aberration,astigmatism, and distortion aberration caused in the exemplary wide-viewanti-vibration zoom lens at the wide-angle end.

FIG. 13 is a graphical view depicting the spherical aberration,astigmatism, and distortion aberration caused in the exemplary wide-viewanti-vibration zoom lens at the telephoto end.

FIG. 14 is a graphical view depicting the comatic aberration caused inthe exemplary wide-view anti-vibration zoom lens at the wide-angle end.

FIG. 15 is a graphical view depicting the comatic aberration caused inthe exemplary wide-view anti-vibration zoom lens at the telephoto end.

BEST MODE OF THE INVENTION Embodiment 1

Table 1 below shows various numerical data on a first preferredembodiment of a wide-view anti-vibration zoom lens according to thepresent invention where all the values are scaled to a normalizedminimum focal length of 1 millimeter (mm). In Table 1, S is a number ofsurfaces, ASPH designates an aspherical surface, R is a radius ofcurvature in millimeters (mm), D is a thickness or a distance inmillimeters (mm), Nd is a refractive index of the d-line (λ=587.6 nm),and ABv is an Abbe constant in relation with the d-line.

Aspherical surfaces can be expressed as in the following formula (20):

$\begin{matrix}{z = {\frac{y^{2}}{{R\left( {1 + \sqrt{1 - {\left( {1 + K} \right){y/R^{2}}}}} \right)}^{2}} + {A\; y^{4}} + {B\; y^{6}} + {C\; y^{8}} + {D\; y^{10}}}} & (20)\end{matrix}$

where z is a depth of the aspherical surfaces, y is a height, R is aparaxial radius of curvature, K, A, B, C, and D denote a degree ofasphericity, and the aspherical surfaces have their respective degreesof asphericity as listed in Table 1 below.

TABLE 1 S R D Nd ABν  1 185.6556 0.4028 1.90366 31.31  2 13.4778 2.83101.49700 81.61  3 −45.0882 0.0355  4 14.5207 1.5745 1.72916 54.67  573.3948 0.0355  6 16.5815 1.0146 1.83481 42.72  7 41.1397 (D7)   8 ASPH13.3663 0.0474 1.53610 41.20  9 10.7661 0.1896 1.88300 40.80 10 2.25121.7006 11 −3.6114 0.1422 1.62004 36.30 12 5.0993 0.7808 1.94595 17.98 13−21.4719 (D13) Aperture 0.0000 1.1848 15 ASPH 4.4935 0.8294 1.6889331.16 16 −29.5955 0.4739 1.83400 37.34 17 4.7393 0.3324 18 5.8020 0.11851.80610 33.27 19 3.6662 0.7453 1.48749 70.44 20 −28.9053 (D20) 21 ASPH3.3229 1.4828 1.69350 53.34 22 ASPH −6.7610 0.0355 23 −13.9305 0.11851.83400 37.34 24 2.4849 1.3766 1.49700 81.61 25 −7.4707 (D25) 26 0.00000.1019 1.51680 64.20 27 0.0000 0.4645 1.61800 63.39 28 0.0000 0.2915 290.0000 0.4028 1.51680 64.20 30 0.0000 3.6730 1.51680 64.20 31 0.0000

Asphericity

NO 8

K: 0.000000

A:0.289736E-02 B:−0.207478E-03 C:0.990963E-05 D:−0.781114E-06

NO 15

K: 0.000000

A:−0.963562E-04 B:−0.376299E-05 C:−0.886104E-05 D:0.116385E-05

NO 21

K: 0.000000

A:−0.777717E-03 B:−0.305060E-03 C:0.758612E-04 D:0.405168E-05

NO 22

K: 0.000000

A:0.543664E-02 B:−0.931646E-03 C:0.340591E-03 D:−0.317582E-04

Focal Length 1.000 4.343 19.082 F-Number 1.6500 2.600 3.600 2ω 76.51219.236 4.476 D7 0.1659 8.0156 12.0596 D13 12.3677 4.5178 0.4739 D203.3875 2.1578 2.1485 D25 0.4229 1.6528 1.6620

In the first preferred embodiment of the wide-view anti-vibration zoomlens, as shown in FIG. 1, the second lens group G2 to the fourth lensgroup G4 are respectively moved during the zooming. Alphanumeric symbolsD7, D13, D20, and D25 in Table 1 respectively designate intervals fromone of the lens group to the next for the varied focal length of theoptics during the zooming. The focal length is 1 millimeter (mm) in FIG.1( a), 4.343 mm in FIG. 1( b), and 19.0828 mm in FIG. 1( c).

Various types of aberration of the first preferred embodiment of thewide-view anti-vibration zoom lens are depicted in FIG. 2 to FIG. 6. Inthese figures, C, d, e, F and g denote C-line (656.28 nm), d-line(587.56 nm), e-line (546.07 nm), F-line (486.13 nm), and g-line (435.84nm), respectively.

FIG. 2 graphically depicts various types of aberration caused in thezoom lens at the wide-angle end (focal length of 1 mm) where graphsrepresent (a) spherical aberration, (b) astigmatism, and (c) distortionaberration, respectively.

FIG. 3 also graphically depicts the various types of aberration causedin the zoom lens at the telephoto end (focal length of 19.082 mm) wheregraphs represent (a) spherical aberration, (b) astigmatism, and (c)distortion aberration, respectively.

FIG. 4 graphically depicts comatic aberration under conditions of thevaried incident angle of beams, including (a) 38.25 degrees, (b) 28.58degrees, (c) 20.93 degrees, and (d) 0 degree each of which values is of½ of the angle of view.

FIG. 5 graphically depicts the comatic aberration caused in the zoomlens at the telephoto end (focal length of 19.082 mm) under conditionsof the varied incident angle of beams, including (a) 2.238 degrees, (b)1.566 degrees, (c) 1.119 degrees, and (d) 0 degree each of which valuesis also of ½ of the angle of view.

The first preferred embodiment of the wide-view anti-vibration zoom lenssatisfies the requirements given as in the following formulae:

f3/f4=3.34  (13-1)

v4=67.48  (14-1)

BFw/Y=6.798  (15-1)

|f1/f2|=6.661  (16-1)

0.4<|f1·1/(v1×fw)|=0.514  (17-1)

H31>H32  (18)

(R31−R32)/(R31+R32)=−0.0266  (19-1)

Embodiment 2

Various numerical data on a second preferred embodiment of the wide-viewanti-vibration zoom lens according to the present invention are listedin Table 2 similar to Table 1 where all the values are scaled to anormalized minimum focal length of 1 millimeter (mm).

TABLE 2 S R D Nd ABν  1 187.9572 0.3910 1.90366 31.31  2 14.5051 2.59791.49700 81.61  3 −43.7127 0.0355  4 14.6879 1.5034 1.72916 54.67  584.1369 0.0355  6 16.2351 0.8569 1.83481 42.72  7 32.0543 (D7)   8 ASPH13.9932 0.0474 1.53610 41.20  9 10.1102 0.1896 1.88300 40.80 10 2.15641.5658 11 −3.2917 0.1422 1.88300 40.80 12 −14.2180 0.0355 13 25.70720.1422 1.90366 31.31 14 9.7156 0.6672 1.94595 17.98 15 −9.7156 (D15)Aperture 0.0000 1.1848 17 3.9627 0.7054 1.66680 33.05 18 72.3795 0.21331.81474 37.03 19 ASPH 4.3789 0.4823 20 8.9702 0.1422 1.80610 33.27 215.3991 0.7017 1.48749 70.44 22 −14.5476 (D22) 23 ASPH 3.4274 1.54031.69350 53.34 24 ASPH −8.8883 0.0355 25 −19.9651 0.1422 1.83400 37.34 262.4171 1.1256 1.49700 81.61 27 −7.6964 (D27) 28 0.0000 0.1019 1.5168064.20 29 0.0000 0.4645 1.61800 63.39 30 0.0000 0.2915 31 0.0000 0.40281.51680 64.20 32 0.0000 3.6730 1.51680 64.20 33 0.0000

Asphericity

NO 8

K:0.000000

A:0.441430E-02 B:−0.302347E-03 C:0.942323E-05 D:−0.779714E-06

NO 19

K: 0.000000

A:0.619937E-03 B:0.238222E-04 C:0.207710E-05 D:0.520394E-06

NO 23

K: 0.000000 KC: 100

A:−0.472346E-03 B:−0.153297E-03 C:0.316449E-04 D:0.293466E-05

NO 24

K: 0.000000 KC: 100

A:0.389191E-02 B:−0.346053E-03 C:0.935950E-04 D:−0.330355E-05

Focal Length 1.0000 4.5023 19.1001 F-Number 1.6500 2.5600 3.5000 2ω76.702 18.512 4.477 D7 0.21327 8.50533 12.52530 D15 12.78615 4.494120.47393 D22 3.69930 2.34682 2.09961 D27 0.61417 1.96649 2.21405

In the second preferred embodiment of the wide-view anti-vibration zoomlens, as shown in FIG. 6, the second lens group G2 to the fourth lensgroup G4 are moved during the zooming. Alphanumeric symbols D7, D15,D22, and D27 in Table 2 respectively designate intervals from one of thelens group to the next for the varied focal length of the optics duringthe zooming. The focal length is 1 millimeter (mm) in FIG. 6( a), 4.5023mm in FIG. 6( b), and 19.1001 mm in FIG. 6( c).

Various types of aberration of the second preferred embodiment of thewide-view anti-vibration zoom lens are depicted in FIG. 7 to FIG. 10similar to FIG. 2 to FIG. 5.

FIG. 7 graphically depicts various types of aberration caused in thezoom lens at the wide-angle end (focal length of 1 mm) where graphsrepresent (a) spherical aberration, (b) astigmatism, and (c) distortionaberration, respectively.

FIG. 8 also graphically depicts the various types of aberration causedin the zoom lens at the telephoto end (focal length of 19.1001 mm) wheregraphs represent (a) spherical aberration, (b) astigmatism, and (c)distortion aberration, respectively.

FIG. 9 graphically depicts comatic aberration caused in the zoom lens atthe wide-angle end (focal length of 1 mm) under conditions of the variedincident angle of beams, including (a) 38.35 degrees, (b) 28.55 degrees,(c) 20.92 degrees, and (d) 0 degree each of which values is of ½ of theangle of view.

FIG. 10 graphically depicts the comatic aberration caused in the zoomlens at the telephoto end (focal length of 19.1001 mm) under conditionsof the varied incident angle of beams, including (a) 2.238 degrees, (b)1.565 degrees, (c) 1.119 degrees, and (d) 0 degree each of which valuesis also of ½ of the angle of view.

The second preferred embodiment of the wide-view anti-vibration zoomlens satisfies the requirements given as in the following formulae:

f3/f4=2.83  (13-2)

v4=67.48  (14-1)

BFw/Y=7.019  (15-2)

|f1/f2|=6.901  (16-2)

0.4<|f1·1/(v1×fw)|=0.556  (17-2)

H31>H32  (18)

(R31−R32)/(R31+R32)=−0.0499  (19-2)

Embodiment 3

Various numerical data on a third preferred embodiment of the wide-viewanti-vibration zoom lens according to the present invention are listedin Table 3 similar to Table 1 where all the values are scaled to anormalized minimum focal length of 1 millimeter (mm).

TABLE 3 S R D Nd ABV  1 187.2038 0.4028 1.90366 31.31  2 14.5735 2.59601.49700 81.61  3 −44.7867 0.0355  4 14.7986 1.5404 1.72916 54.67  595.9716 0.0355  6 16.3270 0.8559 1.83481 42.72  7 31.2796 (D7)   8 ASPH17.6748 0.0474 1.53610 41.20  9 11.7523 0.1896 1.88300 40.80 10 2.19341.5313 11 −3.3743 0.1422 1.88300 40.80 12 −14.2180 0.0355 13 26.51080.1422 1.90366 31.31 14 9.6641 0.6703 1.94595 17.98 15 −9.6641 (D15)Aperture 0.0000 1.1848 17 ASPH 3.4609 0.7833 1.68893 31.16 18 44.08760.1422 1.80610 33.27 19 3.6180 0.5368 20 8.0360 0.1422 1.80610 33.27 214.9364 0.7131 1.48749 70.44 22 −15.9885 3.6402 23 ASPH 3.3850 1.50061.69350 53.34 24 ASPH −8.8783 0.0355 25 −20.0260 0.1422 1.83400 37.34 262.4171 1.1653 1.49700 81.61 27 −7.7420 (D27) 28 0.0000 0.1019 1.5168064.20 29 0.0000 0.4645 1.61800 63.39 30 0.0000 0.2915 31 0.0000 0.40281.51680 64.20 32 0.0000 3.6730 1.51680 64.20 33 0.0000 0.00

Asphericity

NO 8

K: 0.000000

A:0.455156E-02 B:−0.351639E-03 C:0.207200E-04 D:−0.141884E-05

NO 17

K: 0.000000

A:−0.599626E-03 B:−0.315997E-04 C:−0.512130E-05 D:−0.300620E-06

NO 23

K: 0.000000

A:−0.467940E-03 B:−0.302658E-03 C:0.654116E-04 D:−0.204795E-05

NO 24

K: 0.000000

A:0.411688E-02 B:−0.619840E-03 C:0.162231E-03 D:−0.120261E-04

Focal Length 1.000 4.500 19.042 F-Number 1.65 2.60 3.60 2ω 76.76 18.524.487 D7 0.2133 8.5862 12.6312 D15 12.8918 4.5189 0.4739 D22 3.64022.2958 2.0626 D27 0.4803 1.8247 2.0578

In the third preferred embodiment of the wide-view anti-vibration zoomlens, as shown in FIG. 11, the second lens group G2 to the fourth lensgroup G4 are moved during the zooming. Alphanumeric symbols D7, D15,D22, and D27 in Table 3 respectively designate intervals from one of thelens group to the next for the varied focal length of the optics duringthe zooming. The focal length is 1 millimeter (mm) in FIG. 11( a),4.5000 mm in FIG. 11( b), and 19.042 mm in FIG. 11( c).

Various types of aberration of the third preferred embodiment of thewide-view anti-vibration zoom lens are depicted in FIG. 12 to FIG. 15similar to FIG. 2 to FIG. 5.

FIG. 12 graphically depicts various types of aberration caused in thezoom lens at the wide-angle end (focal length of 1 mm) where graphsrepresent (a) spherical aberration, (b) astigmatism, and (c) distortionaberration, respectively.

FIG. 13 also graphically depicts the various types of aberration causedin the zoom lens at the telephoto end (focal length of 19.042 mm) wheregraphs represent (a) spherical aberration, (b) astigmatism, and (c)distortion aberration, respectively.

FIG. 14 graphically depicts comatic aberration caused in the zoom lensat the wide-angle end (focal length of 1 mm) under conditions of thevaried incident angle of beams, including (a) 38.38 degrees, (b) 28.61degrees, (c) 20.94 degrees, and (d) 0 degree each of which values is of½ of the angle of view.

FIG. 15 graphically depicts the comatic aberration caused in the zoomlens at the telephoto end (focal length of 19.042 mm) under conditionsof the varied incident angle of beams, including (a) 2.243 degrees, (b)1.570 degrees, (c) 1.121 degrees, and (d) 0 degree each of which valuesis also of ½ of the angle of view.

The third preferred embodiment of the wide-view anti-vibration zoom lenssatisfies the requirements given as in the following formulae:

f3/f4=2.75  (13-3)

v4=67.48  (14-1)

BFw/Y=6.843  (15-3)

|f1/f2|=6.961  (16-3)

0.4<|f1·1/(v1×fw)|=0.559  (17-3)

H31>H32  (18)

(R31−R32)/(R31+R32)=−0.0222  (19-3)

The prior art embodiment in the cited Patent Document 1 as a firstaspect meets the requirements given as in the following formulae:

f3/f4=1.056  (13-4)

v4=61.85  (14-2)

BFw/Y=8.542  (15-4)

|f1/f2|=6.398  (16-4)

0.4<|f1·1/(v1×fw)|=1.4465  (17-4)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.636  (19-4)

A second embodiment in the cited Patent Document 1 meets therequirements given as in the following formulae:

f3/f4=1.057  (13-5)

v4=61.85  (14-2)

BFw/Y=8.536  (15-5)

|f1/f2|=6.276  (16-5)

0.4<|f1·1/(v1×fw)|=1.713  (17-5)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.405  (19-5)

A third embodiment in the cited Patent Document 1 satisfies therequirements given as in the following formulae:

f3/f4=0.983  (13-6)

v4=65.85  (14-3)

BFw/Y=8.630  (15-6)

|f1/f2|=6.283  (16-6)

0.4<|f1·1/(v1×fw)|=1.656  (17-6)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.533  (19-6)

A fourth embodiment in the cited Patent Document 1 meets therequirements given as in the following formulae:

f3/f4=1.368  (13-7)

v4=65.85  (14-3)

BFw/Y=9.970  (15-7)

|f1/f2|=6.152  (16-7)

0.4<|f1·1/(v1×fw)|=0.692  (17-7)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.481  (19-7)

The prior art embodiment in the cited Patent Document 2 as a firstaspect meets the requirements as in the following formulae:

f3/f4=1.709  (13-8)

v4=50.55  (14-4)

BFw/Y=9.972  (15-8)

|f1/f2|=5.728  (16-8)

0.4<|f1·1/(v1×fw)|=0.722  (17-8)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.142  (19-8)

A second embodiment in the cited Patent Document 2 meets therequirements as in the following formulae:

f3/f4=2.026  (13-9)

v4=52.1  (14-5)

BFw/Y=10.488  (15-9)

|f1/f2=5.797  (16-9)

0.4<|f1·1/(v1×fw)|=0.696  (17-9)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.222  (19-9)

A third embodiment in the cited Patent Document 2 meets the requirementas in the following formulae:

f3/f4=2.232  (13-10)

v4=50.55  (14-6)

BFw/Y=10.496  (15-10)

|f1/f2|=5.745  (16-10)

0.4<|f1·1/(v1×fw)|=0.705  (17-10)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.245  (19-10)

The prior art embodiment in the cited Patent Document 3 as a firstaspect satisfies the requirements given as in the following formulae: asin the following formulae:

f3/f4=1.762  (13-11)

v4=70.55  (14-7)

BFw/Y=11.486  (15-11)

|f1/f2|=5.099  (16-11)

0.4<|f1·1/(v1×fw)|=0.639  (17-11)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.144  (19-11)

A second embodiment in the cited Patent Document 3 meets therequirements as in the following formulae:

f3/f4=1.533  (13-12)

v4=59.9  (14-8)

BFw/Y=11.657  (15-12)

|f1/f2|=5.618  (16-12)

0.4<|f1·1/(v1×fw)|=0.840  (17-12)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.231  (19-2)

A third embodiment in the cited Patent Document 3 meets the requirementsas in the following formulae:

f3/f4=1.347  (13-13)

v4=57.5  (14-9)

BFw/Y=11.540  (15-13)

|f1/f2=5.623  (16-13)

0.4<|f1·1/(v1×fw)|=0.736  (17-13)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.160  (19-13)

A fourth embodiment in the cited Patent Document 3 meets therequirements as in the following formulae:

f3/f4=1.352  (13-14)

v4=57.5  (14-9)

BFw/Y=11.594  (15-14)

|f1/f2|=5.678  (16-14)

0.4<|f1·1/(v1×fw)|=0.854  (17-14)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.165  (19-14)

A fifth embodiment in the cited Patent Document 3 meets the requirementsas in the following formulae:

f3/f4=1.276  (13-15)

v4=64.95  (14-10)

BFw/Y=9.486  (15-15)

|f1/f2|=5.513  (16-15)

0.4<|f1·1/(v1×fw)|=0.744  (17-15)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.161  (19-15)

A sixth embodiment in the cited Patent Document 3 meets the requirementsas in the following formulae:

f3/f4=1.626  (13-16)

v4=61.85  (14-11)

BFw/Y=11.628  (15-16)

|f1/f2|=5.641  (16-16)

0.4<|f1·1/(v1×fw)|=0.834  (17-16)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.089  (19-16)

A seventh embodiment in the cited Patent Document 3 meets therequirements as in the following formulae:

f3/f4=1.801  (13-17)

v4=59.5  (14-12)

BFw/Y=11.656  (15-17)

|f1/f2|=4.272  (16-17)

0.4<|f1·1/(v1×fw)|=0.372  (17-17)

H31<H32  (18-1)

(R31−R32)/(R31+R32)=−0.300  (19-17)

1. A high magnification compact zoom lens comprising: a first lens groupof positive refractivity, a second lens group of negative refractivity,a third lens group of positive refractivity, and a fourth lens group ofpositive refractivity, in order from the object side; the second lensgroup being movable toward the imaging plane and the fourth lens groupbeing movable to compensate for a varied position of the resultant imagewhile the first and third lens groups have their respective positionsfixed along the optical axis, when the entire lens optics of the zoomlens are displaced from the wide-angle end to the telephoto end; whereinthe zoom lens satisfies the requirements as defined in the followingformulae:f3/f4>2.0  (13)v4>65  (14) where f3 is a focal length of the third lens group, f4 isthe focal length of the fourth lens group, and v4 is an average of Abbeconstants of all positive lens pieces in the fourth lens group; andwherein the third lens group has a fixed lens subset of aconvexo-concave cemented lens followed by a movable lens subset of aconcavo-convex cemented lens, the movable lens subset being shifted indirections orthogonal to the optical axis so as to cause incident beamsto be imaged in shifted position, and the fixed lens subset has itsconvex surface of the greater curvature faced closest to the subject andits concave surface of the greater curvature faced closest to theimaging plane, and wherein the zoom lens satisfies the requirements asdefined in the following formulae:H31>H32  (18)−0.12<(R31−R32)/(R31+R32)<0.12  (19) where H31 is a height of part ofincident beams on the foremost surface of the leading lens piece in thefixed lens subset of the third lens group on or above the optical axisat the wide-angle end, and H32 is the height of part of the incidentbeams on the foremost surface of the leading lens piece in the movableor image-stabilizing lens subset of the third lens group on or above theoptical axis at the wide-angle end, and where R31 is a radius ofcurvature of the convex surface of the leading lens piece closest to thesubject in the fixed lens subset of the third lens group, and R32 is theradius of curvature of the concave surface of the trailing lens piececlosest to the imaging plane in the fixed lens subset of the third lensgroup.
 2. A high magnification compact zoom lens according to claim 1,wherein the fixed lens subset in the third lens group has one or more ofthe lens pieces provided with an aspherical surface on at least one ofthe opposite sides thereof so as to compensate for comatic aberrationand spherical aberration.
 3. A high magnification compact zoom lenscomprising: a first lens group of positive refractivity, a second lensgroup of negative refractivity, a third lens group of positiverefractivity, and a fourth lens group of positive refractivity, in orderfrom the object side; the second lens group being movable toward theimaging plane and the fourth lens group being movable to compensate fora varied position of the resultant image while the first and third lensgroups have their respective positions fixed along the optical axis,when the entire lens optics of the zoom lens are displaced from thewide-angle end to the telephoto end; wherein the zoom lens satisfies therequirements as defined in the following formulae:f3/f4>2.0  (13)6.0<BFw/Y<8.0  (14) where f3 is a focal length of the third lens group,f4 is the focal length of the fourth lens group, BFw is a distancebetween a rearmost surface of the fourth lens group and the imagingplane at the wide-angle end, and Y is a height of the greatest imagecreated in the imaging plane; wherein the third lens group has a fixedlens subset of a convexo-concave cemented lens followed by a movablelens subset of a concavo-convex cemented lens, the movable lens subsetbeing shifted in directions orthogonal to the optical axis so as tocause incident beams to be imaged in shifted position, and the fixedlens subset has its convex surface of the greater curvature facedclosest to the subject and its concave surface of the greater curvaturefaced closest to the imaging plane, and wherein the zoom lens satisfiesthe requirements as defined in the following formulae:H31>H32  (18)−0.12<(R31−R32)/(R31+R32)<0.12  (19) where H31 is a height of part ofincident beams on the foremost surface of the leading lens piece in thefixed lens subset of the third lens group on or above the optical axisat the wide-angle end, and H32 is the height of part of the incidentbeams on the foremost surface of the leading lens piece in the movableor image-stabilizing lens subset of the third lens group on or above theoptical axis at the wide-angle end, and where R31 is a radius ofcurvature of the convex surface of the leading lens piece closest to thesubject in the fixed lens subset of the third lens group, and R32 is theradius of curvature of the concave surface of the trailing lens piececlosest to the imaging plane in the fixed lens subset of the third lensgroup.
 4. A high magnification compact zoom lens according to claim 3,wherein the fixed lens subset in the third lens group has one or more ofthe lens pieces provided with an aspherical surface on at least one ofthe opposite sides thereof so as to compensate for comatic aberrationand spherical aberration.
 5. A high magnification wide-view zoom lenscomprising: a first lens group of positive refractivity, a second lensgroup of negative refractivity, a third lens group of positiverefractivity, and a fourth lens group of positive refractivity, in orderfrom the object side; the second lens group being movable toward theimaging plane and the fourth lens group being movable to compensate fora varied position of the resultant image while the first and third lensgroups have their respective positions fixed along the optical axis,when the entire lens optics of the zoom lens are displaced from thewide-angle end to the telephoto end; and wherein the zoom lens satisfiesthe requirements as defined in the following formulae:|f1/f2|>6.5  (16)0.4<|f1₁/(v1×fw)|<0.6  (17) where f1 is the focal length of the firstlens group, f2 is the focal length of the second lens group, is thefocal length of the foremost lens piece of the first lens group, v1 isan Abbe constant of the foremost lens piece of the first lens group, andfw is the focal length of the zoom lens at the wide-angle end; whereinthe third lens group has a fixed lens subset of a convexo-concavecemented lens followed by a movable lens subset of a concavo-convexcemented lens, the movable lens subset being shifted in directionsorthogonal to the optical axis so as to cause incident beams to beimaged in shifted position, and the fixed lens subset has its convexsurface of the greater curvature faced closest to the subject and itsconcave surface of the greater curvature faced closest to the imagingplane, and wherein the zoom lens satisfies the requirements as definedin the following formulae:H31>H32  (18)−0.12<(R31−R32)/(R31+R32)<0.12  (19) where H31 is a height of part ofincident beams on the foremost surface of the leading lens piece in thefixed lens subset of the third lens group on or above the optical axisat the wide-angle end, and H32 is the height of part of the incidentbeams on the foremost surface of the leading lens piece in the movableor image-stabilizing lens subset of the third lens group on or above theoptical axis at the wide-angle end, and where R31 is a radius ofcurvature of the convex surface of the leading lens piece closest to thesubject in the fixed lens subset of the third lens group, and R32 is theradius of curvature of the concave surface of the trailing lens piececlosest to the imaging plane in the fixed lens subset of the third lensgroup.
 6. A high magnification wide-view zoom lens according to claim 5,wherein the fixed lens subset in the third lens group has one or more ofthe lens pieces provided with an aspherical surface on at least one ofthe opposite sides thereof so as to compensate for comatic aberrationand spherical aberration.
 7. A high magnification wide-view zoom lenscomprising: a first lens group of positive refractivity, a second lensgroup of negative refractivity, a third lens group of positiverefractivity, and a fourth lens group of positive refractivity, in orderfrom the object side; the second lens group being movable toward theimaging plane and the fourth lens group being movable to compensate fora varied position of the resultant image while the first and third lensgroups have their respective positions fixed along the optical axis,when the entire lens optics are displaced from the wide-angle end to thetelephoto end; and wherein the zoom lens satisfies the requirements asdefined in the following formulae:|f1/f2|>6.5  (16)0.4<|f1₁/(v1×fw)|<0.6  (17) where f1 is a focal length of the first lensgroup, f2 is the focal length of the second lens group, f1 ₁ is thefocal length of the foremost lens piece of the first lens group, v1 isan Abbe constant of the foremost lens piece of the first lens group, andfw is the focal length of the zoom lens at the wide-angle end; and thesecond lens group has one or more of the lens pieces provided with anaspherical surface on at least one of the opposite sides thereof;wherein the third lens group has a fixed lens subset of aconvexo-concave cemented lens followed by a movable lens subset of aconcavo-convex cemented lens, the movable lens subset being shifted indirections orthogonal to the optical axis so as to cause incident beamsto be imaged in shifted position, and the fixed lens subset has itsconvex surface of the greater curvature faced closest to the subject andits concave surface of the greater curvature faced closest to theimaging plane, and that wherein the zoom lens satisfies the requirementsas defined in the following formulae:H31>H32  (18)−0.12<(R31−R32)/(R31+R32)<0.12  (19) where H31 is a height of part ofincident beams on the foremost surface of the leading lens piece in thefixed lens subset of the third lens group on or above the optical axisat the wide-angle end, and H32 is the height of part of the incidentbeams on the foremost surface of the leading lens piece in the movableor image-stabilizing lens subset of the third lens group on or above theoptical axis at the wide-angle end, and where R31 is a radius ofcurvature of the convex surface of the leading lens piece closest to thesubject in the fixed lens subset of the third lens group, and R32 is theradius of curvature of the concave surface of the trailing lens piececlosest to the imaging plane in the fixed lens subset of the third lensgroup.
 8. A high magnification wide-view zoom lens according to claim 7,the fixed lens subset in the third lens group has one or more of thelens pieces provided with an aspherical surface on at least one of theopposite sides thereof so as to compensate for comatic aberration andspherical aberration.